Semiconductor parts and semiconductor mounting apparatus

ABSTRACT

To provide a package structure for securing a satisfactory optical coupling between an optical device arranged beforehand on a printed board and an optical device newly mounted on the particular printed board. Positioning LDs  41   a  and  41   b  are arranged on a printed board  1.  A sensing PD  42   a  for receiving the optical signal emitted from the positioning LD  41   a  and a sensing PD  42   b  for receiving the optical signal emitted from the positioning LD  41   b  are arranged in an OEIC package  11  mounted on the printed board.

This application is a division of prior application Ser. No. 09/259,690filed Mar. 1, 1999.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a structure for interconnection betweensemiconductor chips, between MCMs (multichip modules) or between an MCMand a semiconductor chip packaged on a printed board, or more inparticular to a structure for mounting a semiconductor or an MCMaccurately at a predetermined position on the board in order to obtain asuperior optical coupling between the parts and an optical waveguide foroptical communication between the parts on the printed board.

2. Description of the Related Art

With an increase in signal transmission speed and an increased densityof wirings and parts, the technique of electrically interconnectingparts on a printed board has posed the problem that an increased wiringresistance, due to the skin effect, appears and that crosstalk betweenwiring is caused during communication between the parts. The increasedwiring resistance leads to an increased heat generation and thecrosstalk disturbs the signal waveform causing a malfunction. In thisway, electrical methods of interconnection have almost come to a limitof speed and density.

A method for solving the problem mentioned above is to secure an opticalconnection in which the parts packaged on a printed board communicatewith each other using an optical signal.

FIG. 18 shows a structure for optical communication between the partspackaged on a printed board.

In FIG. 18a, 101 designates a printed board, 102 waveguides, 103 and 104IC packages, 105 electrical circuit chips, 106 optical device arrays,108 leads and 109 ball bumps.

The IC packages 103 and 104 each have built therein the electricalcircuit chip 105 and the optical device array which is an assembly oflight-emitting elements and photo-detectors. This packages is alsocalled an OEIC package in view of the fact that electrical circuits andoptical devices are integrated. Also, the optical device array 106 iselectrically connected with the electrical circuit chips through theball bumps 109. The printed board 101 has buried therein a plurality ofthe waveguides 102 corresponding to the elements of the optical devicearray for transmitting an optical signal exchanged between the partsarranged on the printed board. The leads 108 receive power from a powersupply unit not shown and supply it to the electrical circuit chips 105and the optical devices 106 in the IC packages.

FIG. 18b is a bottom view of the IC packages 103 and 104. In FIG. 18b,112 designates radiation holes of the light-emitting elements of theoptical device array or incidence holes of the photo-detectors.

The diameter of a radiation hole 112 and an incidence hole 112 is about20 μm and the holes are arranged at intervals of about 100 μ.

FIG. 18c is a top plan view of the printed board 101. In FIG. 18c, 121designates pads and 122 openings of waveguides.

The pads 121 are supplied with power from a power supply unit not shownand connected with a power terminal or a GND terminal 108. The openings122 of the waveguides are placed in opposed relation to the radiationholes or the incidence holes 112. The diameter of each opening 122 isabout 50 μm to 90 μm, and the openings are arranged at intervals ofabout 100 micrometers.

With reference to FIGS. 18a to 18 c, the optical communication betweenthe IC package 103 and the IC package 104 will be explained. In thiscase, an optical signal is assumed to be sent from the IC package 103 tothe IC package 104.

The IC packages 103 and 104 are supplied with power from a power supplyunit not shown through the pads 121 and the leads 108.

The electrical circuit chip 105 of the package 103 outputs a signal(electrical signal) to the electrical circuit chip 105 of the package103. The signal output from the electrical circuit chip 105 is convertedinto an optical signal in the light-emitting elements of the opticaldevice array 106, and radiated toward the openings 122 of the waveguidefrom the radiation holes 112. The optical signal passes into thewaveguides 102 from the openings 122, proceeds in the waveguides 102 andis output toward the incidence holes 112 of the IC package 104 from theopenings 122 of the IC package 104. The optical signal received by theIC package 104 is converted into an electrical signal by thephoto-detectors in the optical device array 106 and output to theelectrical circuit chip 105.

The use of the above-mentioned technique of interconnection permitsexchange of an optical signal between parts and eliminates the need ofelectrical connection, obviates the problems of increased wiringresistance and crosstalk, and thus can increase the signal transmissionspeed and the density of parts and wiring.

As shown in FIGS. 18b and 18 c, however, the openings 122 and theradiation and incidence holes 112 of the waveguides are so small thatthe registration between the waveguides and the optical devices requiresa highly accurate optical coupling technique. The registration errormust be controlled to not more than 10 μm. Also, the LD (laser diode)used as the light-emitting element and the PD (photo-diode) used as thephoto-detector have a low heat resistance, and are liable to be brokenby a thermal stress when soldered for packaging.

SUMMARY OF THE INVENTION

The object of the present invention is intended, taking theabove-mentioned problem into consideration, to provide a highly accuratetechnique for optical coupling between parts and a packaging techniqueexerting only a small stress on the optical devices in such an opticalcoupling.

In order to solve the above-mentioned problem, according to theinvention, a socket for receiving a semiconductor part includingphotoelectric elements is arranged on a printed board. The position ofpackaging a semiconductor part on the printed board is defined, andtherefore the accuracy of registry between the optical transmission pathon the printed board and the optical device of the semiconductor part isimproved.

Preferably, the socket includes a power terminal for supplying a sourcevoltage to the photoelectric elements of the semiconductor part.Preferably, the change in the terminal shape of the part can be metsimply by redesigning the socket, and therefore the multipurposeapplicability of the printed board is maintained.

Preferably, the semiconductor part inserted into the socket and theinsertion holes of the socket for the semiconductor part are placed inspaced relation to each other. As a result, the correct position ofarrangement of the semiconductor part is held within a predefined range,resulting in an improved working efficiency.

Preferably, the semiconductor part packaged on the printed boardincludes light-emitting elements for transmitting an optical signal andphoto-detectors for receiving the optical signal emitted by thelight-emitting elements. The semiconductor part emits an optical signal,and receives the optical signal by itself through the optical devicearranged on the printed board. The degree of optical coupling betweenthe printed board and the semiconductor part can be determined.

Preferably, the optical device arranged on the printed board isspecified as an optical transmission path. Unless both thelight-emitting elements and the photo-detectors of the semiconductorpart are optically coupled to the openings of the optical transmissionpath, the semiconductor elements cannot receive the optical signalemitted by themselves. In other words, the structure is such that theregistration between two points of a semiconductor part and two pointsof the printed board can be achieved at the same time by receiving theoptical signal.

Preferably, an optical device for optical communication with thephotoelectric elements arranged on the printed board is included in thesemiconductor part packaged on the printed board. The right packagingposition of the semiconductor part on the printed board can be checkedby optical communication between the printed board and the semiconductorpart and verifying the degree of optical coupling.

Preferably, the semiconductor part includes a plurality of opticaldevices corresponding to the photoelectric elements, respectively,arranged on the printed board. A plurality of points of thesemiconductor part and a plurality of points of the printed board can beregistered with each other, and the semiconductor part can be defined toa single orientation.

Preferably, the semiconductor part includes an electrical circuit chipoperated by the power supplied from an external source and photoelectricelements for exchanging the optical signal and the electrical signalbetween the electrical circuit chip and the optical device on theprinted board. The optical communication is possible between a pluralityof semiconductor parts packaged on the printed board. Therefore, theelectrical wiring is eliminated, and the increased heat generation andcrosstalk which otherwise might occur, due to the increased transmissionrate and the increased density of the transmission path, can besuppressed.

Preferably, there is provided a printed board on which a semiconductorpart including photoelectric elements is packaged, and an opticaltransmission path is arranged for returning the optical signal, emittedby the semiconductor part, to the same semiconductor part. The opticalsignal output from the semiconductor element is returned to theparticular optical signal. Unless the photoelectric elements of thesemiconductor part are optically coupled to both the inlet and outlet ofthe optical transmission path, however, the optical transmission pathcan neither receive nor output the optical signal. In other words, thestructure is such that the registration between two points of thesemiconductor part and two points of the printed board can beaccomplished at the same time by the receipt of the optical signal.

Preferably, photoelectric elements are arranged a printed board forperforming optical communication with an optical device included in asemiconductor part mounted on the printed board. Optical communicationis conducted between the printed board and the semiconductor part, andthe degree of optical coupling is verified, so that the correctpackaging position of the semiconductor part on the printed board can befound.

Preferably, a plurality of photoelectric elements corresponding to therespective optical devices of the semiconductor part are arranged on theprinted board. A plurality of points on the semiconductor parts can beregistered with a plurality of points on the printed board, and theposition of the semiconductor part is defined by a single orientation.

Preferably, there is provided a printed board on which a semiconductorpart including light-emitting elements, photo-detectors andphotoelectric elements is packaged. Further, an optical transmissionpath with an end thereof optically coupled to the light-emittingelements of the semiconductor part and with the other end thereofoptically coupled to the photo-detectors is arranged on the printedboard. The board has such a structure that the optical signaltransmitted from the semiconductor part is returned to the semiconductorpart through the optical transmission path arranged on the printedboard. Superior optical coupling is achieved between two points of theprinted board and two points of the semiconductor part, therebyguaranteeing the arrangement of the semiconductor elements at thecorrect position.

Preferably, there is provided a printed board unit in which asemiconductor part including an optical device is packaged on a boardand further photoelectric elements optically coupled to thesemiconductor part are arranged on the board. Optical communication beperformed between the printed board and the semiconductor part therebyguaranteeing the optical coupling between the two.

Preferably, there is provided a printed board unit in which asemiconductor part including an optical device is fixed by an adhesiveon the board. The semiconductor part is fixed on the printed boardwithout stress, and therefore the durability is improved.

Preferably, there is provided a positioning apparatus in which aposition where an optical signal can be received with high sensitivityis automatically searched for while moving a semiconductor element foroptically communicating with the printed board.

Preferably, the positioning apparatus includes a power terminal forsupplying power to the optical device of the semiconductor part. A partdedicated to registration need not be arranged on the printed board, anda reduction in density of the wiring and the parts on the printed boardcan be prevented.

Preferably, the positioning apparatus is such that the adhesive forfixing the semiconductor part on the printed board is set uponcompletion of the positioning operation. The semiconductor part isautomatically fixed on the printed board.

Preferably, the semiconductor part including an optical device is fixedon the printed board using an adhesive. In other words, the soldering iseliminated, thereby solving the problem that the semiconductor part isbroken by the high-temperature heat generated by the soldering process.

Preferably, the semiconductor part mounted on the printed board and ismoved while optically communicating with the printed board, therebychecking the receiving sensitivity. Relative positions of two mutuallydistant objects can be checked, and the correct position of asemiconductor part on the printed board can be found.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other objects of the present invention will become apparentfrom the following detailed description of the preferred embodiment ofthe invention, taken in connection with the accompanying drawings.

In the drawings:

FIGS. 1a, 1 b, and 1 c are views showing the process of mounting an OEICpackage on a printed board;

FIGS. 2a, 2 b, 2 c, 2 d, and 2 e are views showing a connector socket;

FIGS. 3a, 3 b, 3 c, and 3 d are views showing a first method ofregistration;

FIG. 4 is a diagram showing a second method of registration;

FIG. 5 is a diagram showing a third method of registration;

FIGS. 6a, 6 b, 6 c, and 6 d are views showing a fourth method ofregistration;

FIG. 7 is a diagram showing an adjust plate;

FIG. 8 is a diagram showing the lower part of an adjust plate;

FIG. 9 is a diagram showing a plate supporting frame;

FIG. 10 is diagram showing the manner in which the adjust plate isstored in the plate supporting frame;

FIG. 11 is a diagram showing the structure of an adjustment screw;

FIG. 12 is a diagram showing a positioning unit;

FIGS. 13a, 13 b, and 13 c are views showing the structure of a connectorsocket;

FIGS. 14a and 14 b are views showing a function block diagram of apositioning unit;

FIG. 15 is a first flowchart for registration;

FIG. 16 is a second flowchart for registration;

FIGS. 17a and 17 b are views showing the structure of a rotating ball;and

FIGS. 18a, 18 b, and 18 c are views showing the prior art.

DETAILED DESCRIPTION OF THE INVENTION

Embodiments of the present invention will be explained below.

FIGS. 1a to 1 c are diagrams showing the process of mounting an OEICpackage on a printed board. Sectional views of the printed board and theOEIC package mounted on the printed board are shown in each drawing.

In FIGS. 1a to 1 c, 1 designates a printed board, 2 waveguides, 3 aconnector socket, 4 power terminals or ground terminals, 6 an adhesive,11 an OEIC package, 12 an optical device array, 13 an electrical circuitchip and 14 a package-side power terminal or ground terminal.

FIG. 1a shows the first step of mounting.

The OEIC package 11 has sealed therein the optical device array 12 andthe electrical circuit chip 13, which are electrically connected to eachother through ball bumps 15. The optical device array 12 has arrangedthereon LDs (laser diodes) as light-emitting elements and PDs(photo-diodes) as photo-detectors. The electrical signal output from theelectrical circuit chip 13 is modulated into an optical signal by theLDs, and the optical signal received by the PDs is demodulated into anelectrical signal and applied to the electrical circuit chip 13.

The printed board 1 has buried therein the waveguides 2 corresponding tothe elements of the optical device array, respectively, and the opticalsignal exchanged between the OEIC package 11 and other electronic partsmounted on the printed board 1 is transmitted through the waveguides 2.Each waveguide is an optical fiber made of glass or the like.

Also, the connector socket 3 is mounted on the printed board 1 andreceives the OEIC package 11. The connector socket 3 includes a terminal4 supplied with a source voltage and a ground voltage from a powersupply unit not shown. The OEIC package 11 is also provided with a powerterminal and a ground terminal 14, so that by contacting the terminals 4on the connector socket side, the source voltage and the ground voltageare supplied to the optical device array 12 and the electrical circuitchip 13 in the OEIC package 11. The number of the terminals 4 and of theterminals 14 is not specifically determined. The terminals can beassigned for power and ground connection, respectively, or a pluralityof terminals may be assigned for power or ground connection.

FIGS. 2a- 2 e show the connector socket. Each connector socket has apower supply terminal or a ground terminal 4, which will not bedescribed here.

The connector socket 3 shown in FIG. 2a is made of a member having asquare-framed flat surface and an L-shaped section.

The connector socket 3 shown in FIG. 2b, on the other hand, includes apair of members in opposed relation to each other each having achannel-shaped upper surface and an L-shaped section. The connectorsocket 3 shown in FIG. 2b is useful in the case where the terminal 14 ofthe OEIC package 11 is arranged only on a pair of the opposed sides ofthe OEIC package 11.

The connector socket 3 shown in FIG. 2c is comprised of members eacharranged along each side of a rectangle and having a rod-shaped uppersurface and an L-shaped section.

The connector socket 3 shown in FIG. 2d is comprised of members arrangedin opposed relation to each other each and each having an L-shaped uppersurface and an L-shaped section. The members are provided at least at apair of corners of a rectangle. The OEIC package 11 received by theconnector socket 3 shown in FIG. 2d is mounted on the printed board 1with the corners thereof surrounded by the members of the connectorsocket 3.

FIG. 2e is a sectional view of the connector sockets 3 shown in FIGS. 2ato 2 d. In FIG. 2e, 7 designates an exterior wall, and 8 a base. Themovable range of the OEIC package loaded into the connector socket 3 islimited by the exterior wall 7, and the terminal 14 is mounted on thebase 8. The connector socket shown in each of FIGS. 2a to 2 d hasterminals 4 protruded from the inner surface of the exterior wall 7 andextending onto the base 8. Each terminal 14 of the OEIC 11 comes intocontact with the terminal 4 located on the base 8. A maximum space of100 μm is formed between the terminal 14 of the OEIC package and theouter wall 7 of the connector socket 3.

When the connector socket shown in any of FIGS. 2a to 2 d is used, theterminals 14 of the OEIC package 11 are all mounted on the base 8 of theconnector socket 3. However, the base 8 of the connector socket may beomitted and the terminals 4 can be arranged on the printed board 1. Sucha connector socket is effective for receiving the OEIC package since theterminals 14 of the OEIC package are led out from the bottom surface butnot from the side surfaces of the package.

FIG. 1b shows the second step of the mounting process. The OEIC packageis loaded in an area defined by the connector socket 3. An adhesive 6 iscoated in an area away from the terminals 14 on the inside of the outerwall 7 of the connector socket and on the base 8. A thermosetting resinor an ultraviolet light-setting resin is used as the adhesive.

FIG. 1c shows the third step of the mounting process. The OEIC package11 is mounted on the printed board 1, so that the terminals 4 of theconnector socket 3 and the terminals 15 of the OEIC 11 are brought intocontact with each other and the waveguide 2 is set in registry with theelements of the optical device array 12.

Registration methods will be explained below.

With reference to FIGS. 3a- 3 d, a first registration method will beexplained.

In FIGS. 3a- 3 d, a marking 9 is attached on the connector socket. Themarking 9 and the edge of the OEIC package 11 are two-dimensionallyoverlapped, so that the elements of the optical device array 12 of theOEIC package are placed in opposed relation with the correspondingwaveguides 2 thereby to achieve a superior optical coupling. FIGS. 3a to3 b all show that the OEIC package 11 is loaded into the connectorsocket 3 as viewed from the top. In this case, although the connectorsocket shown in FIG. 2a is used, the connector socket shown in any ofFIGS. 2b to 2 d can be used.

In FIG. 3a, a marking 9 is attached at each of four predetermined pointson the base 8. Each marking 31 is hook-shaped. in the registration usingthe marking shown in FIG. 3a, each corner of the OEIC package 11 istwo-dimensionally overlapped with the marking, so that the OEIC packageis set in position. For setting the OEIC package 11 of FIG. 3a inposition, the OEIC package 11 is moved left upward.

In FIG. 3a, although markings are attached at four points, respectively,a marking can be attached only at any one of the points. Desirably,however, markings are attached at least at two points.

In FIG. 3b, a frame-shaped marking is attached along the base 8 of theconnector socket 3. When using the marking shown in FIG. 3b, theposition of the OEIC package 11 is adjusted in such a manner that theperipheral edge of the OEIC package is overlapped with the marking.

In FIG. 3c, a linear marking is attached on each side of the base 8 ofthe connector socket 3. When using the marking shown in FIG. 3c, theposition of the OEIC package is adjusted by overlapping each markingwith the corresponding side of the OEIC package. The markings, thoughattached on the four sides of the base 8, respectively, in FIG. 3c, mayalternatively be attached only on two orthogonal sides.

In FIG. 3d, spot markings are attached on the base 8 of the connectorsocket 3. Spot markings are required to be attached on at least a pairof orthogonal sides or at least at two corners of the base 8. When usingthe marking shown in FIG. 3d, the position of the OEIC package isadjusted in such a manner that all the spots are overlapped with theedge of the OEIC package 11 at the same time.

The markings shown in FIGS. 3a to 3 e are all attached on the base 8 ofthe connector socket 3. When using a connector socket without a base, onthe other hand, a marking is attached on the printed board in an areadefined by the connector socket. Any shape shown in FIGS. 3a to 3 d canbe used for such a marking.

Also, a combination of the shapes can be used as a marking.

With reference to FIG. 4, a second registration method will beexplained. As shown in FIG. 4, through holes 31 are formed at least attwo predetermined positions in an area of the printed board 1 defined bythe connector socket 3, and spot marks 32 corresponding to therespective through holes are attached on the back of the OEIC package11.

In a second method of registration, the OEIC package 11 is moved in sucha manner that all the spot marks 32 can be checked through thecorresponding through holes 31 when the printed board 1 is viewed fromthe back. In the state where all the spot marks 32 and the through holes31 are overlapped with each other, each element of the optical devicearray 12 of the OEIC package 11 is in opposed relation to acorresponding to waveguide 2, and a superior optical coupling isattained.

The matching between the through holes 31 and the spot marks 32 can bechecked also by a method, other than direct viewing as in theabove-mentioned example. For example, the picture is taken of the backof the printed board 1 with camera, and the image picked up by thecamera is displayed in a display unit while the OEIC package 11 is movedto search for the position where the through holes 31 are overlappedwith the spot marks 32.

Also, the through holes is not necessarily a circle, but may be atriangle, a rectangle or an other polygon or an ellipse. The marks ofthe OEIC package 11 are also not necessarily spots, but can be changedin shape in accordance with the shape of the through holes.

Further, although the through holes 31 are formed on the printed board 1and the marks 32 are formed on the OEIC package 11 in the exampledescribed above, the through holes 31 can be formed on the OEIC package11 and the marks 32 can be formed on the packaged surface of the printedboard 1.

With reference to FIG. 5, a third method of registration will beexplained. As shown in FIG. 5, recesses are formed at least at twopoints on the printed board 1, and protrusions 34 are formed on thesurface of the OEIC package 11 facing the printed board (the back of theOEIC package 11)

In the third method of registration, the OEIC package 11 is moved in thedirection in which the protrusions 34 are overlapped with thecorresponding recesses 33 on the printed board 1, and the registrationis completed when all the protrusions are fitted in the correspondingrecesses.

In the examples described above, the recesses 33 are formed in theprinted board 33 and the protrusions 34 are formed on the OEIC package.Instead, the protrusions 34 can be formed on the package surface of theprinted board while the recesses 33 can be formed on the back of theOEIC package.

Also, the recesses are preferably formed apart from each other, and soare the protrusions. Especially, it is desirable to form them at opposedcorners of rectangles.

With reference to FIGS. 6a- 6 d, a fourth method of registration will beexplained. In the fourth method of registration, an accurate position ofarrangement of the OEIC package 11 is detected by use of an opticalsensor.

In FIG. 6a, numerals 41 a and 41 b designate positioning LDs, numeral 42a and 42 b sensing PDs, numeral 5 a power unit, and numeral 43 a monitorunit.

The positioning LDs 41 a and 41 b are arranged in the optical devicearray 12 of the OEIC package 11 and output an optical signal forregistration. The sensing PDs 42 a and 42 b are both embedded in theprinted board 1 for receiving the optical signals output from thepositioning LDs 41 a, 41 b and converting them into electrical signals,respectively. The PD can be replaced by a photo-transistor. Thepositioning LDs 41 a and 41 b are supplied with a source voltage fromthe power unit 5 through the terminals 4 arranged on the connectorsockets 3 and the terminals 14 arranged on the OEIC package 11. Thesensing PDs 42 a and 42 b are supplied with a source voltage from thepower unit 5 through a predetermined layer of the printed board. Themonitor unit 43 monitors the electrical signals output from the sensingPDs 42 a, 42 b. The output signals of the sensing PDs 42 a, 42 b arereceived by the monitor unit 43 through a predetermined layer in theprinted board.

The positioning LDs 41 a, 41 b output an optical signal toward thepackage surface of the printed board 1. Unless the OEIC package 11 isplaced in position, the optical signals output from the positioning LDsare not received by the sensing PDs arranged on the printed board 1. Theregistration between the terminals 4 and the terminals 41 has a widetolerance. Even when the OEIC package 11 is not placed in position butas long as it is located within the connector socket, the connection ismaintained between the terminals 4 and 41, and power continues to besupplied to the positioning LDs.

In order to set the OEIC package 11 in position, the first step ofoperation is to secure the optical coupling between the positioning LD41 a and the sensing PD 42 a. A method for this will be explained below.

The OEIC package 11 is arranged at a predetermined position (X0, Y0) onthe X-Y coordinate defined on the printed board. The coordinate on theprinted board is stored in a robot, which moves the OEIC package to thepoint (X0, Y0). The worker moves the OEIC package 11 according to thesteps described in 1 to 4 below and searches for the coordinate point(Xj, Yj) where the maximum output can be produced from the sensing PD 42a.

1. While maintaining a constant Y coordinate, the OEIC package 11 ismoved in parallel to X axis to the farthest end in the movable range.Assume that the X coordinate of the farthest point is Xmax. The movingdistance to Xmax is about 100 μm.

2. While keeping the X coordinate at Xmax, the OEIC package 11 is movedin parallel to the Y axis by a very small distance Y1. Y1 is about 100μm.

3. While maintaining the Y coordinate constant, the OEIC package 11 ismoved in parallel to the X axis until the coordinate X0 is reached alongthe X axis.

4. While maintaining the X coordinate at X0, the OEIC package 11 ismoved by a very small distance Y1 in parallel to the Y axis.

The OEIC package, when moved according to 1 to 4 above, moves to thecoordinate point (Xmax, Ymax). Ymax is the farthest end point in themovable range. The distance to Ymax is about 100 μm.

While the OEIC package 11 is moving, the output level of the sensing PD42 a is monitored by the monitor unit 43. The monitor unit 43, upondetection that a signal exceeding a preset level is output from thesensing PD 42 a, outputs a positioning-over signal and gives aninstruction to stop the movement of the OEIC package 11 visibly oraudibly.

Upon complete registration between the positioning LD 41 a and thesensing PD 42 a, the operation is performed to secure optical couplingbetween the positioning LD 41 b and the sensing PD 42 b. The manner inwhich such optical coupling is secured will be described below.

The OEIC package 11 located at the coordinate point (Xj, Yj) is rotatedaccording to the steps described in 5 and 6 below, and a coordinatepoint is found where the maximaum output is produced from the sensing PD42 b.

5. With the coordinate point (Xp, Yp) of the sensing PD 42 a as arotational axis, the OEIC package 11 is rotated by θ1 incounterclockwise direction.

6. With the coordinate point (Xp, Yp) of the sensing PD 42 a as arotational axis, the OEIC package 11 is rotated by θ1+θ2 in clockwisedirection.

In the foregoing description, θ1 and θ2 are the maximum movable angle ineach direction of rotation and assume a value within the range of one totwo degrees.

While the OEIC package 11 is moving, the output level of the sensing PD42 b is monitored by the monitor unit 43. The monitor unit 43, upondetection that a signal exceeding a preset level is output from thesensing PD 42 b, outputs a positioning-over signal and gives a visibleor audible instruction to stop the rotation of the OEIC package 11.

According to the steps 1 to 6 described above, the positioning LDs 41 aand 41 b are set in registry with the sensing LDs 42 a and 42 b,respectively, and the orientation of the OEIC package 11 is defined. Atthe same time, the elements constituting the optical device array 12 areoptically coupled with the corresponding waveguides 2 of the printedboard 1. After complete registry, the adhesive 6 is set to fix the OEICpackage 11 on the printed board 1.

In the example shown in FIG. 6a, the positioning LDs 41 a and 41 b areboth arranged on the OEIC package 11, while the sensing PDs 42 a and 42b are both arranged on the printed board 1. Alternatively, as shown inFIG. 6b, one of the positioning LDs may be arranged on the printed board1 and one of the sensing PDs may be arranged on the OEIC package 11.Also, as shown in FIG. 6c, the positioning LDs 41 a and 41 b may be botharranged on the printed board 1, while the sensing PDs 42 a and 42 b maybe both arranged on the OEIC package 11 with equal effect. Theelectrical signals output from the sensing PDs arranged on the OEICpackage 11 are applied to the monitor unit 43 through the terminals 14and 4.

In the examples shown in FIGS. 6a to 6 c, at least two pairs of thepositioning LDs and the sensing PDs are required. Nevertheless, anexplanation will be given below of a positioning method using one pairof a positioning LD and a sensing PD.

In FIG. 6d, the positioning LD 41 a and the sensing PD 42 a are botharranged in the OEIC package 11. A return waveguide 44 for returning theoptical signal emitted from the positioning LD 41 a to the sensing PD 42a is buried in the printed board 1. The positioning LD 41 a and thesensing PD 42 a are both supplied with power from the power unit 5through the terminals 4 and 14. The electrical signal output from thesensing PD 42 a is similarly output to the monitor unit 43 through theterminals 15 and 4.

In order to arrange the OEIC package 11 in position, the operation isperformed for optically coupling the positioning LD 41 a and the sensingPD 42 a. The process of this operation will be described below.

The OEIC package 11 is arranged at a predetermined position (X0, Y0) onthe X-Y coordinate defined on the printed board. The coordinates on theprinted board are stored in a robot for conveying the OEIC package tothe point (X0, Y0). The worker moves the OEIC package 11 according tothe steps described in 7 to 11 below thereby to search for a coordinatethat can produce a maximum output from the sensing PD 42 a.

7. While maintaining a constant Y coordinate, the OEIC package 11 isinched by a minute distance each time in parallel to X axis to thefarthest end point in the movable range. Assume that the X coordinate atthe farthest end point is Xmax. The moving distance the distance to Xmaxis about 100 μm.

8. While maintaining the X coordinate at Xmax, the OEIC package 11 isinched each time in parallel to the Y axis and moved by a distance Y1.Y1 is a distance of about 10 μm.

9. While maintaining a constant Y coordinate, the OEIC package 11 isinched by a minute distance each time in parallel to X axis until thecoordinate X0 along the X axis is reached.

10. While maintaining the X coordinate at X0, the OEIC package 11 isinched in parallel to the Y axis each time by a minute distance Ys untilit covers Y1.

11. In each step of 7 to 10 above, each time the OEIC package 11 isinched by Xs or Ys, it is rotated by ±θ about the X-Y coordinates at theoutlet and the inlet of the return waveguide 44.

While the OEIC package 11 is being moved, the output level of thesensing PD 42 a is monitored by the monitor unit 43. The monitor unit43, upon detection that a signal exceeding a preset level is output fromthe sensing PD 42 a, outputs a positioning-over signal, and gives anoptical or aural instruction to stop the movement of the OEIC package11.

FIGS. 7 to 11 show component parts for moving the OEIC package 11 asdescribed with reference to steps 1 to 6 and 7 to 11, respectively.

FIG. 7 discloses members for holding the OEIC package and members formoving the same.

In FIG. 7, numeral 51 designates an OEIC holder, 52 an X-Y coordinateadjust plate, 53 a rotation adjust plate, 54 a rotation pole and 55 aninlet.

The OEIC holder 51 has a recess and holds therein the OEIC package 11.The X-Y coordinate adjust plate 52 moves the OEIC holder 51 in the X andY directions. The rotation adjust plate 53 rotates the OEIC holder 5about the rotation pole 54. The inlet 55 has inserted therein a duct forsucking the OEIC package. The OEIC package thus sucked is attracted tothe OEIC holder 61 and fixed in orientation.

The OEIC holder 51, the X-Y coordinate adjust plate 52 and the rotationadjust plate 53 described above are integrated with each other throughthe rotation pole 54. Among these members, the OEIC holder 51 and therotation adjust plate 53 are fixed to the rotation pole 54, and with therotation of the rotation adjust plate 53, the OEIC holder 51 alsorotates. The X-Y coordinate adjust plate 52 is rotatably mounted on therotation pole and is not operatively interlocked with the rotation ofthe rotation adjust plate 53. When the X-Y coordinate adjust plate 52moves along the X or Y axis, the other members (the rotation pole 54,the OEIC holder 51 and the rotation adjust plate 53) also move in thesame direction.

FIG. 8 is a diagram showing the members of FIG. 7 as viewed diagonallyfrom the bottom thereof. Numeral 56 designates a suction port to whichthe OEIC package held in the OEIC holder 51 is adsorbed.

FIG. 9 shows a plate supporting frame 61 for supporting the membersshown in FIGS. 7 and 8.

In FIG. 9, numeral 62 designates a first stage, 63 a second stage, 64legs for supporting the first stage 62 and the second stage 63, and 65pin holes.

The first stage 62 has mounted thereon the X-Y coordinate adjust plate52. The second stage 63 is arranged on the upper layer of the firststage 62 and has mounted thereon the rotation adjust plate 53. The legs64 sandwich the connector sockets 3 so that the whole supporting frameis fixed on the printed board 1. The pin holes 65 have inserted thereinadjust pins for moving the X-Y coordinate adjust plate 52 and therotation adjust plate 53. The pin holes 65 are formed in the four sidesof the first stage 62 and two orthogonal sides 2 of the second stage 63.The supporting frame 61 shown in FIG. 12 with the plates mounted thereonis placed on the printed board 1. When the supporting frame 61 is placedon the printed board 1 with the connector sockets 3 held by the legs 64,the sensing PD 42 a of FIG. 6a and the positioning LD 41 a of FIGS. 6band 6 c are located just under the rotation pole 54, and the OEICpackage 11 can be rotated about a point (Xp, Yp).

FIG. 10 shows the state in which the adjust plates shown in FIG. 7 aremounted on the plate supporting frame 61.

In FIG. 10, 71 a designates an X-direction adjust pin, 71 b anX-direction urge pin, 72 a a Y-direction adjust pin, 72 b a Y-directionurge pin, 73 a counterclockwise adjust pin, and 74 a clockwise adjustpin.

The X-direction adjust pin 71 a moves along the X axis by the distancecorresponding to the rotation amount thereby to move the X-Y coordinateadjust plate 51 along the X axis. The X-direction urge pin 71 b isarranged in opposed relation to the X-direction adjust pin 71 a and isurged toward the X-direction adjust pin 71 a by spring or the like. TheY-direction adjust pin 72 a moves along the Y axis by the distancecorresponding to the rotation amount, and moves the X-Y coordinateadjust plate 52 along the Y axis. The Y-direction urge pin 72 b isarranged in opposed relation to the Y-direction adjust pin 72 a, and isurged toward the Y-direction adjust pin 72 a by spring or the like. Thecounterclockwise adjust pin 73 moves along the Y axis by the distancecorresponding to the rotation amount and rotates the rotation adjustplate 53 counterclockwise. The clockwise adjust pin 74, on the otherhand, moves along the X axis by the distance corresponding to therotation amount and rotates the rotation adjust plate 53 clockwise.

With the configuration shown in FIG. 10, the X-Y coordinate adjust plate52 is held between an adjust pin and an urge pin and thus fixed inorientation. The rotation adjust plate 53, on the other hand, is fixedin orientation by being held between the counterclockwise adjust pin 73and the clockwise adjust pin 74.

FIG. 11 shows the structure of an adjust pin and an urge pin. Thestructure of the X-direction adjust pin 71 a and the X-direction urgepin 71 b will be explained as a typical adjust pin and a typical urgepin, respectively, of the adjust pins shown in FIG. 10. In the drawing,75 designates a reference socket, and 76 a coil spring.

The reference socket 75 is laid through the outer frame of the firststage 62 and the forward end thereof reaches an area defined by an outerframe. The surface at the forward end portion of the reference socket 75is formed with threads. The adjust pin 71 a has a recess around therotational axis at the forward end thereof for receiving the referencesocket 75 and formed with threads to engage the threads of the referencesocket 75. The adjust pin 71 a is moved along the X axis by rotatingaround the reference socket 75. The urge pin 71 b is laid through theouter frame of the first stage 71 and the forward end thereof reaches anarea defined by the outer frame. A spring 76 is wound around the forwardend of the urge pin 71 b and held between the outer frame and the pintop. The spring 76 is extensible along the X axis thereby to urge thepin 71 b toward the adjust pin 71 b. The X-Y coordinate adjust plate 52is held between the adjust pin 71 a and the urge pin 71 b. The adjustpin 71 a, a by rotating in clockwise direction, moves toward the urgepin 71 b thereby to move the X-Y coordinate adjust plate 52 in +Xdirection. On the other hand, the adjust pin 71 a, by rotating incounterclockwise direction, moves in the direction opposite to the urgepin 71 b. The X-Y coordinate adjust plate 52 thus pushed in the -Xdirection by the urge pin. The OEIC holder 51 is operatively interlockedwith the X-Y coordinate adjust plate 52 and therefore moves in the samedirection as the X-Y coordinate adjust plate 52. As a result, the OEICpackage 11 held in the OEIC holder 51 is also moved.

An explanation will be given of a positioning unit for automaticallyadjusting the position of the OEIC package 11.

FIG. 12 shows a positioning unit used according to this embodiment.

In FIG. 12, numeral 81 designates a positioning unit, 82 a rotatingball, and 83 a power terminal or a ground terminal.

The positioning unit 81 is placed on the connector socket 3. Therotating ball 82 is rotated in contact with the upper surface of theOEIC package 11 thereby to move the OEIC package 11. A plurality of theterminals 83 are provided and inserted into the connector sockets 3.These terminals come into contact with the corresponding terminals 4,respectively, to supply a source voltage and a ground voltage to thepositioning LDs and the sensing PDs in the OEIC package 11. Also, asource voltage is supplied from the terminals 83 of the positioning unitto the positioning LDs 41 and the sensing PDs 42 buried in the printedboard. Further, the electrical signal output from the sensing PDs issupplied to the positioning unit 81 through the terminals 83. Thepositioning unit 81 detects the output of the sensing PDs and accordingto the intensity thereof, controls the rotation of the rotating ball 82.The positioning unit 81, upon detection that the OEIC package 11 isarranged in position, discharges hot air (in the case where the adhesive6 is a thermosetting resin) or ultraviolet light (in the case where theadhesive 6 is an ultraviolet light-setting resin) toward the printedboard 1 and thereby sets the adhesive 6.

FIGS. 13a- 13 c show the structure of the connector socket 3 of FIG. 12.

In FIG. 13a, numerals 86 a and 86 b designate insertion holes of theterminals 83. The insertion holes 86 a have inserted therein theterminals 83 conducting with the positioning LDs or the sensing PDs inthe OEIC package 11. The insertion holes 86 b, on the other hand, haveinserted therein the terminals 83 conducting with the positioning LDs orthe sensing PDs buried in the printed board. FIG. 13b shows thestructure for securing the conduction between a terminal 83 and aterminal 14 of the OEIC package, and FIG. 13c shows a structure forsecuring the conduction between a terminal 83 and an element buried inthe printed board 1.

FIGS. 14a and 14 b show an internal function block diagram of thepositioning unit. In FIGS. 14a and 14 b, numeral 91 designates a powersupply unit, 92 a, 92 b, 92 c motors, 93 a control circuit and 94 adischarge section.

The power supply unit 91 supplies a source voltage and a ground voltageto the positioning LDs and the sensing PDs of the OEIC package 11through the terminals 83. The motors 92 a, 92 b, 92 c drive the rotatingball 82 along X axis, Y axis and in the X-Y plane in the direction ofangle θ. The control circuit 93 detects the output of the sensing PDsreceived from the terminals 83, and according to the intensity thereof,controls the drive of the motors. The discharge section 94 dischargestoward the printed board the hot air (in the case where the adhesive 6is a thermosetting resin) for setting the adhesive 6 for fixing the OEICpackage 11 or the ultraviolet light (in the case where the adhesive 6 isan ultraviolet light-setting resin). FIG. 14a takes the registrationbetween the OEIC package and the printed board shown in FIG. 6a intoconsideration, and FIG. 14b takes the registration between the OEICpackage and the printed board shown in FIG. 6d into consideration. Whenthe registration between the OEIC package and the printed board shown inFIG. 6b or FIG. 6c is taken into consideration, on the other hand, thepositions of the positioning LDs and the sensing PDs shown in FIG. 14aare exchanged with each other.

Now, a method of adjusting the position where the OEIC package isarranged will be explained with reference to the positioning unit 81shown in FIG. 12.

First, the registration between the OEIC package and the printed boardshown in FIGS. 6a to 6 c will be explained.

The OEIC package 11 is arranged at a predetermined position (X0, Y0) onthe X-Y coordinate defined on the printed board. Each coordinate on theprinted board is stored in a robot not shown, which robot conveys theOEIC package 11 to point (X0, Y0). Once the OEIC package is placed atpoint (X0, Y0), the positioning unit 51 is mounted on the printed board1. The positioning unit 51 moves the OEIC package according to the stepsdescribed in 12 to 18 and searches for a coordinate point (Xj, Yj) wherethe maximum output is produced from the sensing PD 42 a.

FIG. 15 is a control flowchart for the positioning unit 81. Steps S12 toS17 shown in FIG. 15 will be explained below.

S12: The power supply unit 91 supplies power to the positioning LDs, thesensing PDs and the function blocks in the positioning unit 81.

S13: The control unit 93 drives only the motor 92 a and moves the OEICpackage 11 in parallel to X axis to the farthest end point in themovable range. Assume that the X coordinate of the farthest end point isXmax. The control circuit 93 stores the rotational speed of the motorrequired for moving the OEIC package to Xmax. The distance to Xmax isabout 100 μm.

S14: The control circuit 93 drives only the motor 92 b and moves theOEIC package 11 in parallel to Y axis by a minute distance Y1. Y1 isabout 10 μm. The control circuit 93 stores the rotational speed of themotor required for moving the OEIC package by Y1.

S15: The control circuit 93 drives only the motor 82 a, and moves theOEIC package 11 in the direction parallel to X axis until the coordinatealong X axis reaches X0.

S16: The control circuit 93 drives only the motor 92 b, and moves theOEIC package 11 in the direction along Y axis by a minute distance Y1.

The OEIC package, when driven according to Steps S12 to S16 describedabove, moves to the coordinate (Xmax, Ymax). Ymax is the farthest endcoordinate in the movable range along Y axis. The distance to Ymax isabout 100 μm.

S17: While the OEIC package 11 is moving, the output level of thesensing PD 42 a is monitored by the control circuit 93. The controlcircuit 93, upon detection of the fact that a signal exceeding a presetlevel is output from the sensing PD 42 a, outputs a stop signal to themotor being driven. The motor that has received the stop signal stopsrotating the rotating ball.

S18: As an alternative, each time the OEIC package 11 is inched, theprevailing coordinate or the coverage of distance to that point (thetotal number of revolutions of the motor driven) is stored in a table,and after the OEIC package is moved to a predetermined position (Xmax,Ymax), the OEIC package is returned to a position where the maximumoutput can be produced.

Upon complete registration between the positioning LD 41 a and thesensing PD 42 a, the operation is performed for optically coupling thepositioning LD 41 b and the sensing PD 42 b. A method of this operationwill be explained below.

The OEIC package 11 located at the coordinate (Xj, Yj) is rotatedaccording to the steps described in Steps S19 to S28 below and acoordinate is searched for where the maximum output can be produced fromthe sensing PD 42 b.

S19: The control circuit 93 drives only the motor 92 c and therebyrotates the OEIC package 11 in counterclockwise direction by θ1 aboutthe coordinate point (Xp, Yp) of the sensing PD 42 b. In this case, thepositioning unit 81 is designed, when placed on the printed board 1 withthe terminals 83 inserted in the connector sockets 3, to locate thecoordinate point (Xp, Yp) just under the rotating ball 82.

S20: The control circuit 93 drives only the motor 92 c, and rotates theOEIC package 11 clockwise by θ1+θ2 about the coordinate point (Xp, Yp)of the sensing PD 42 a.

The angles θ and θ2 are maximum movable angles in each direction ofrotation and assume a value not more than about one to two degrees.

S17′: While the OEIC package 11 is moving, the output level of thesensing PD 42 a is monitored by the control circuit 93. The controlcircuit 93, upon detection that a signal exceeding a preset level isoutput from the sensing PD 42 a, outputs a stop signal to the motorbeing driven. The motor that has received the stop signal stops drivingthe rotating ball.

S18′: As an alternative, each time the OEIC package 11 is inched, theprevailing coordinate or the coverage of distance up to that point (thetotal number of revolutions of the motor driven) is stored in a table,and after rotating the OEIC package to a predetermined angle (θ=θ2), theOEIC package can be returned to the position associated with the maximumoutput.

The OEIC package and the printed board are designed in such a mannerthat when the positioning LDs 41 a and 41 b are set in position by thesensing PDs 42 a and 42 b, respectively, each element constituting theoptical device array 12 is set in registration with a correspondingreturn waveguide 44. Upon complete registration, the control circuit 93outputs a positioning-over signal to the discharge unit 94. In responseto the positioning-over signal, the discharge unit 94 discharges hot air(in the case where the adhesive is a thermosetting resin) or ultravioletlight (in the case where the adhesive is an ultraviolet light-settingresin) toward the printed board.

Now, an explanation will be given of a method of setting the OEICpackage of FIG. 6d in position on the printed board using thepositioning unit 81. In the case under consideration, assume that thepositioning unit 81 is in contact with the OEIC package and iscontrolled by a rotating ball 84 different from the rotating ball 82 andthe control circuit 93, and includes a motor 95 for driving the rotatingball 84 in the direction of θ.

The OEIC package ii is placed at a predetermined position (X0, Y0) ofthe X-Y coordinates defined on the printed board. Each coordinate on theprinted board is stored in a robot, so that the OEIC package 11 isconveyed by the robot to point (X0, Y0). The positioning unit 81, on theother hand, moves the OEIC package 11 according to the steps of steps 21to 29 described below, and searches for the orientation of the OEICpackage in which the maximum output can be produced from the sensing PD42 a.

FIG. 16 is a control flowchart for the positioning unit 81. Steps S21 toS29 shown in FIG. 16 will be explained below.

S21: Power is supplied from the power supply unit 91 to the positioningLDs, the sensing LDs and the function blocks in the positioning unit 81.

S22: The control circuit 93 drives only the motor 92 a, so that the OEICpackage 11 is moved by a minute distance Xs each time in the directionparallel to X axis to the farthest end of the movable range. The Xcoordinate at the farthest end point is assumed as Xmax. The controlcircuit 93 stores the number of revolutions of the motor required formoving the OEIC package 11 to Xmax.

S23: The control circuit 93 drives the motor 92 b alone and moves theOEIC package 11 in parallel by the distance Y1, a minute distance Ys ata time. The control circuit 69 stores the number of revolutions of themotor required for moving the OEIC package 11 by the distance Ys.

S24: The control circuit 93 drives only the motor 92 a, and moves theOEIC package 11, a minute distance Xs each time, in parallel to X axisuntil the X coordinate becomes X0.

S25: The control circuit 93 drives only the motor 92 b, and moves theOEIC package 11, a minute distance Ys each time, along Y axis by Y1.

S26: In each of Steps S21 to S25 above, the control circuit 93 firstdrives only the motor 93 b, and each time the OEIC package 11 is movedby Xs or Ys, rotates the OEIC package 11 by ±θ1 about the coordinatepoint (Xo, Yo) at the discharge port of the return waveguide 44. Thecontrol circuit 63 has stored therein the number of revolutions of themotor required for rotating by the angle θ1. Also, in the case underconsideration, the positioning unit 81 is designed, when placed on theprinted board 1 with the terminals 81 inserted in the connector socket3, to locate the point (Xo, Yo) just under the rotating ball 82.

Next, only the motor 95 is driven, so that the OEIC package 11 isrotated by ±θ1 about the coordinate (Xi, Yi) at the entrance port of thereturn waveguide 44. The control circuit 93 stores the number ofrevolutions of the motor required for rotating by angle θ1. Also, inthis case, the positioning unit 81 is designed, when placed on theprinted board 1 with the terminals 83 inserted in the connector socket3, to locate the point (Xi, Yi) just under the rotating ball 84.

S27: While the OEIC package 11 is moving, the output level of thesensing PD 42 a is monitored by the detection circuit 93. The detectioncircuit 93, upon detection that a signal exceeding a preset level isoutput from the sensing PD 42 a, outputs a signal to stop the motorbeing driven. The motor that has received the stop signal stops therotation of the rotating ball.

S28: As an alternative, each time the OEIC package is moved by a minuteangle or by a minute distance, the coordinate involved or the distancecovered by the OEIC package (total number of revolutions of the motors)and the output of the sensing PD 42 a are stored in a table. After theOEIC package has been moved to a predetermined range, the OEIC packagecan be returned to the position where the maximum output can beproduced.

The OEIC package and the printed board are so designed that when thepositioning LD 41 a and the sensing PD 42 a are set in registry with theinlet and the outlet of the waveguide, respectively, the elements makingup the optical device array 12 are set in registry with thecorresponding outlets of the return waveguide 44. Upon completeregistration, the control circuit 93 outputs a positioning-over signalto the discharge unit 94. The discharge unit 94, in response to thepositioning-over signal, discharges hot air (in the case where theadhesive is a thermosetting resin) or ultraviolet light (in the casewhere the adhesive is an ultraviolet light-setting resin) toward theprinted board.

With reference to FIGS. 17a and 17 b, the structure of the rotating ball82 will be explained.

In FIG. 17a, numerals 97 a, 97 b, 97 c designate rollers. The roller 97a is driven by a motor 92 a thereby to move the rotating ball along theX axis. The roller 97 b is driven by a motor 92 b thereby to move therotating ball along the Y axis. The roller 97 c is driven by a motor 92c thereby to rotate the rotating ball in the direction θ. Each roller isadapted to contact or leave the rotating ball freely. A roller under thecontrol of the motor stopped leaves the rotating ball, while the rollerunder the motor being driven contacts the rotating ball. There is norotating ball 85 corresponding to the roller 97 a or 97 b, but a roller(corresponding to 97 c) is provided which is driven by the motor 95 forrotating the rotating ball 85 in the direction of angle θ.

FIG. 17b is a side view showing a rotating ball. 98 designates anopening of the positioning unit, and 99 a fixed cylinder. The opening 98is arranged on the bottom surface of the positioning unit 81 and is asmall circular hole having a diameter smaller than that of the rotatingball 82. The rotating ball is placed on the opening 98 and partlyexposed under the positioning unit. The fixed cylinder 99 is arranged onthe rotating ball 82 which in turn is placed on the opening 98, so thatpart of the rotating ball is covered by the fixed cylinder 99. Theopening 98 and the fixed cylinder 99 prevent the rotating ball fromrolling.

The embodiments described above are intended for application to thesemiconductor parts mounted on a printed board and an OEIC package. Theinvention, however, is also applicable to a multi-chip module in which aplurality of chips are arranged on a ceramic board.

According to this invention, a connector socket for receivingsemiconductor parts having photoelectric elements is installed on aprinted board. By arranging the semiconductor elements in the connectorsocket, the correct position for the semiconductor parts can be checkedwithin a defined range, and therefore the working efficiency isimproved. Also, the degree of optical coupling is checked by opticalcommunication between the printed board and the semiconductor partsmounted thereon. As a result, relative positions of two distant objectscan be determined, and the correct position of the semiconductor partsarranged on the printed board can be checked. Further, since thesemiconductor parts with an optical device mounted thereon are fixed ona printed board using an adhesive, the soldering, which exerts thermalstress, is eliminated, thereby securing the safety of the parts.

It is to be understood that the invention is by no means limited to thespecific embodiments illustrated and described herein, and that variousmodifications thereof may be made which come within the scope of thepresent invention as defined in the appended claims.

What is claimed is:
 1. A socket installed on a printed board having anoptical device, for positioning of a semiconductor part which has aphotoelectric element and a terminal, the socket installed with thephotoelectric element of the semiconductor part arranged to opticallycommunicate with the optical device of the printed board, the socketcomprising: a base; exterior walls extending from the base to form aspace for receipt of the semiconductor part; and a socket terminal forconnection to the terminal of the semiconductor part.
 2. The socket asdefined in claim 1, wherein said socket terminal is an electric terminaland the terminal of the semiconductor communicates with the socketterminal upon insertion of the semiconductor part into the space of thesocket.
 3. The socket as defined in claim 1, wherein after insertion ofthe semiconductor part into the socket, a gap exists between thesemiconductor part and the exterior walls of the socket so that thesocket is usable for a rough positioning and subsequent accuratepositioning is carried out within the region of said gap.